Antibacterial and anti-fungal activity of citrus (Citrus unshiu) essential oil extracted from peel by-products

Abstract

Antibacterial and anti-fungal activities of citrus essential oil (CEO) were determined to examine possible use of the food processing by-product as a functional material for food and cosmetic composition. Bacillus subtilis, Staphylococcus aureus, Esherichia coli, Candida albicans, and Aspergillus niger were used to investigate antimicrobial activity of the CEO against general human skin resident microflora. For specific disease-related microornisms, Trichophyton rubrum and T mentagrophytes were used for tinea pedis (athlete's foot) and Pityrosporum ovale (ATCC 12078) for dandruff. Major compound in CEO is limonene (89.4% +/- 1.40). Growths of B. subtilis, S. aureus, and E. coli were inhibited by adding 0.1% CEO in designated broth, resulting in approximately 2-3 decimal reduction. C. albicans and A. niger were almost eliminated by 0.1% CEO addition. T rubrum and T. mentagrophytes showed 90.9 and 81.7% reductions, respectively. P ovale was eliminated by adding 0.1% CEO. These results indicate that CEO can be used as a natural component for antibacterial or anti-fungal activity in food and cosmetics.